Coolant tubing

What is your question?

I have a 2000 328i that still runs hot, I can drive for about 15 minute then temp will go into red, I have replaced my coolant reservoir due to there being a small leak in it, water pump and thermostat as well just because it can’t hurt, it fixed the smoking in the engine but caused a small leak in another tube under and to the left a little of the oil filter, I cannot figure out the tube for the life of me and auto shops can not tell me exactly what tube it is so that I can order. This is causing no leaks until in the red, then barely smokes enough to see

What makes this problem better or worse?

It’s better when only driven short distances

How long has your 2000 BMW 328i had this problem?

A few months